Temperature responsive device



Sept. 8, 1936.

L. E. SMITH TEMPERTUREA RESPONS IVE .DEVICE Filed Deo. 14, 1954 u s (wwwINVENTOR L E SM1 TH TTORNEY Patented sept s. 193s l 2,053,974- "I UNITEDsTATEs PATENT oFFlcE TEMPERATURE aEsroNsrvx nevica Lawrence E. Smith,Rochester, N. lY., assigner to- Taylor Instrument Companies, Rochester,N. Y., a corporation of New York Application December 14,1984, SerialNo. '157,543

11 claims. (ci. zar-si,

This invention relates to temperature responsystem including aBourdonspring 8 which is consive devices and more particularly tovapor-acnected by a capillary tube 'I to a bulb 8. 'lfhc tuated tubesystems therefor. Bourdon spring. the capillary tube and a portion Inone type of temperature responsive device, -of the bulb 8 of the tubesystem is filled with a the thermo-sensitive unit thereof comprisesatube liquid, such as methyl ether, which vaporizes to 6 systemincludinga bulb communicating through create a greater vapor pressure whenexposed to j a capillary tube with a Bourdon spring or other a risingtemperature and which partially liqueiles pressure responsive element,which tube system is to decrease the vapor pressure as the'temperapartially filled with a liquid that vaporiz as the ture isreduced. The free end o! the Bourdon subjectedto heat. .The changingvapor pressure. pivoted at Il. The penV arm at itsfree end is resultingfromthe vaporization and condensation provided with a stylus Illaengaging a graduated' of the liquid, actuates the Bourdon springoi' thechart I2 rotated in accordance with time by suittube system. In such anarrangement it is deable clock mechanism of which only the arbor I8 ltube system and particularly the bulb thereof is spring 8 is connected'byra linkgto a pen arm I8 10 sirable to compensate for the varyingtemperais indicated. 5 ture conditions about the capillary tube and theInorderto compensate for temperature changes Bourdon spring. occurringabout the Bourdon spring 8 and the Since every vapor-iilled tube systemmay be accapillary tube 1 inside the instrument 1case and cidentallyexposed to temperatures higher than near it so that this portion oi' thetube system is those for which it was'intended for use, it hasunresponsive to varying temperature conditions, a@

been proposed to provide means-to protect the the temperaturecompensating and overload pro- Bourdon spring'or pressure responsiveelement tecting unit Il of the present invention is prothereof againstdamage by the excessive pressure vided. As best illustrated in Fig. 2,this unit developed in the system 'as a result oi such ex which ismounted on a xed support such as the. posure. back of the instrumentcase 5, includes a metal Agg;

In accordance with the present invention a spring bellows i5, theinterior oi which comnovel temperature compensating and overload ormunicates through a branch capillary tube I8, protective means isprovided for a vapor-actuated with the main capillary tube "l so thatthe liquid tube system, which means is connected to the capin the tubesystem can ilow into and out 'of the l illary tube of the system and canbe mounted bellows I5. A cylindrical plug i1 preferably 30 within thecase of the instrument or can be lomade of material such as invar havinga low col cated at any point along the capillary tube -where efficientof expansion, is provided within the belit may be desirable to effecttemperature compenlows to decrease the volume of the liquid withinsation. the bellows to a minimum amount and yet to per- For a clearerunderstanding of the invention mit expansion and contraction of thebellows. 35 reference is made to the drawing in which` Fig. 1 The letthand end of bellows I5 is vsecured to a illustrates a tube system and aninstrument case xed bracket I8 attached to the back of the inof a.vapor-actuated temperature recorder, a porstrument case, while the otherend of the bellows tion of the front of the instrument case being isattached to a movable yoke I8. This unit also broken away to indicategenerally the construcincludes a second bellows 28 which is completely40 tion of the operating mechanism therein; Fig. 2 iilled with a liquidhaving the same or diiierent is an enlarged view of the tube system with.the characteristics as compared with the liquid used temperaturecompensating and overload protecin the tube system. The left end ofthebellows tive unit of Fig. 1 attached thereto, said unit being 28 isattached to fixed brackets 2i mounted on the partially in section; Fig.3 is a sectional view of back of the instrument, while the right handend 45 the unit taken on the line 3 3 of Fig. 2; Fig. 4 of this bellowsis secured toa plate 22 carried on is a sectional view of a modiiiedtype oi temthe right end of movable yoke I8. An adjustable peraturecompensating and overload protective coil spring 23y at one end, isattached to the plate unit which may be substituted for that shown in22' and is attached at its other end to an adjust- Fig. 2; and Fig. 5 isa sectional view ot this modi-f ing bolt and nut 24 which is carried bya bracket l450 ed unit taken on the line 5-5 of Fig. 4. 25 projectingfrom the back of the instrument Referring especially to Fig. l, 5designates an case. It will be understood that by tightening orinstrument case within which there is mounted loosening the-nut withrespect to its bolt the stress the operating mechanism of a temperaturereon spring 28 canbe varied.

corder. This mechanism is operated by a tube The general operation oithe instrument is the 55 same as that oi' former instruments, that is,when additional liquid in the partially illled bulb .8 vaporizes on arise in temperature, the vapor pressure increases in the tube systemcausing the Bourdon spring to unwind. 'I'his motion of the spring istranslated through the link 8 into a clockwise movement oi' the pen armI0 so that the stylus Illa carried thereby records the temperaturechange on the graduated chartiZ. A drop in temperature about the bulb 8permits some of the vapor in the bulb 8 to liquefy and thereby reducesthe pressure in the tube system so that the instrument operates in thereverse sense from that just described in connection with a rise intemperature.

The function of the unit I4 of the present invention is as follows: Whenthe liquid illling medium in the Bourbon spring 6 and in the capillarytube 1 expands due to a temperature change in the atmosphere surroundingthem, the liquid iilled bellows 28 will likewise expand. This willcompress the coil spring 23 and will move the yoke I9 toward the right(Fig. 2) causing bellows i5 to expand so that space is provided thereinfor the excess expanded filling liquid from the Bourdon spring andcapillary tube which excess liquid would otherwise be displaced into thebulb 8. The use of the present arrangement renders it unnecessary'tomake the bulb 8 oversized to take care of changes in volume in theliquid due to lack of compensation.

On a drop in temperature about the Bourdon spring 6 and the capillarytube 1, the liquid in the bellows 20 will contract and the coil spring23 will force the yoke I9 toward the left so that the bellows I5 willtend to contract thereby'insuring liquid in the capillary tube, theBourdon spring and a partion of the bulb in spite of the varyingtemperature thereabout. The coil spring 23 may be so adjusted that whenthe bulb 8 is overheated thereby increasing the pressure in the tubesystem beyond its spring pressure rating, the bellows i5 connectedthrough the branch capillary tube Ii to the main capillary tube 1 willbe allowed to expand, thereby removing all of the liquid from the bulbitseli' and thus decreasing the vapor pressure in the system so thatexcesbracket I8 and its other end secured to a movai ble plate 28. Thisplate is provided with a guide rod 21 preferably coinciding with themain axis of the bellows IIa which guide rod is slidable in an openingin a fixed bracket 28. A coil spring 29 having one of its ends insertedin an opening in the guide rod 21 has its other end secured in anopening in a bolt 30. This bolt passes through an opening in a bracket8| and is engaged by a nut I2 to change the adjustment of the stress onthe spring 28. Within the bellows I5a there is mounted a completelysealed bellows 20a which is illled with a liquid having characteristicssimilar to that of the liquid employed in the tube system, or any othersuitable liquid that changes its volume when subjected to varyingtemperatures. T'his bellows has one end iixed to the plate |5b of thebellows lia and has its other end positioned adjacent the plate 26 ofbellows I 5a. The bellows 20a reduces the volume of the liquid containedin bellows |5a and as it expands its free end engages the plate 26 toexpand the bellows lia in like manner against the action of spring 28.This unit otherwise functions in the same manner as the :first-mentionedunit but has the advantage that it is somewhat more compact than thatunit.

While the invention has been disclosed in connection with a tube systememploying a Bourdon spring, the invention is not to be limited to thatconstruction. It will be understood that the present arrangement isapplicable to tube systems which utilize other pressure responsiveelements, such as diaphragms, instead oi.' Bourdon springs.

I claim:

1. In a device o! the class described, a tube system comprising a bulbcommunicating with a Bourdon spring through a capillary tube, avaporizable liquid partially filling said tube system, an expansiblechamber communicating with said tube system, a second sealed chambercontaining a temperature responsive liquid therein whereby said secondchamber expands and contracts in response to varying temperatureconditions, and means for increasing and decreasing the volume of saidilrst chamber as the volume of said second chamber respectivelyincreases and decreases.

2. In a device of the class described, a tube system comprising a bulbcommunicating with a Bourdon spring through a capillary tube, avaporizable liquid completely illling said Bourdon spring, saidcapillary tube and a portion of said bulb, an expansible chambercommunicating with said capillary tube, a relatively inert element insaid chamber to reduce the volume thereof, a fixed support to which oneend of said chamber is attached, a yoke attached to the other end ofsaid chamber, a second completely sealed expansible chamber having atemperature responsive liquid therein, one end ot said second chamberbeing secured to a fixed support adjacent said other end of the ilrstchamber, the other end ot said second chamber being attached to saidyoke whereby a change in volume in said second chamber eiects acorresponding change in volume in said ilrst chamber.

3. In a device of the class described, a tube system comprising a bulbcommunicating with a Bourdon spring through a capillary tube, avaporizable liquid completely iilling said Bourdon spring, saidcapillary tube and a portion of said bulb, an expansible chambercommunicating with said capillary tube, a relatively inert element insaid chamber to reduce the volume thereof, a xed support attached to oneend of said chamber, a yoke attached to the second end ot said chamber,a second completely sealed expansible chamber having a temperatureresponsive liquid therein, one end of said second chamber being securedto a fixed support adjacent the second end of the ilrst chamber, theother end o! said second chamber being attached to said yoke whereby achange in volume in said second chamber effects a corresponding changein volume in said rst chamber, and an adjustable spring engaging the endof said yoke.

4. In a system of the class described, a tube system comprising a bulbcommunicating with a Bourdon spring through a capillary tube, avaporizable liquid lling said Bourdon spring, said 'capillary tube and aPortion oi' said bulb, an expansible chamber communicating with saidcapillary tube said chamber having one of its ends ilxed and having itsother end acting against a spring, a second completely sealed 'chamberlled with a temperature responsive liquid, said second chamber beingmounted within said ilrst chamber whereby the tube system is compensatedfor varying temperature conditions about said capillary tube and Bourdonspring.

5. In a device of the character described, a tube system comprising abulb communicating with a pressure-responsive element through acapillary tube, liquid medium normally lling said element and tube aswell as a portion only of said bulb, at least a portion of said mediumbeing vaporizable, an expansible chamber communicating with said tubesystem, said chamber being expansible under vapor pressure in said tubesystem to such a volume as to permit said liquid medium t passcompletely out of said bulb when the bulb is heated beyond a giventemperature, and means responsive to varying temperature conditionsaround a portion of said tube system exclusive of said bulb for varyingthe volume of said chamber.

6. In a device' of the character described, a tube system comprising abulb and a pressure responsive element communicating with each otherthrough a capillary tube, liquid medium normally iilling said elementand tube as well as a portin A only of said bulb, at least a portion ofsaid medium being vaporizable, an expansible chamber of large sizecommunicating with said capillary tube, a member of relatively inertmaterial within said chamber to reduce the volume thereof, said chamberbeing expansible under vapor pressure in said tube system to such avolume as to permit said liquid medium to pass completely out of saidbulb when the bulb is heated beyond a given temperature, and meansresponsive to varying temperature conditions around said element andcapillary tube for varying the volume of said chamber.

7. In a device of the character described, a tube system comprising abulb communicating with a pressure-responsive element through acapillary tube, liquid medium normally filling said element and tube aswell as a portion only of said bulb, at least a portion of said mediumbeing vaporizable, an expansible chamber communicating with said tubesystem, said chamber being expansible under vapor pressure in said tubesystem to such a volume as to permit said liquid medium to passcompletely out of said bulb when the bulb is heated beyond a giventemperature, and means including a sealed expansible chamber containinga liquid responsive to varying temperature conditions around saidelement and capillary tube, said means serving to vary the volume oisaid mst-mentioned chamber.

8. In a device of the character described. a tube system comprising a.bulb communicating with a pressure responsive element through acapillary tube, liquid medium normally illing I said element and saidcapillary tube as well as a portion only of said bulb, an expansiblechamber communicating with said tube system, said chamber beingexpansible under vapor pressure in said tube system to such a volume asto permit said liquid medium to pass completely out of said bulb whenthe bulb is heated beyond a given temperature, and means for exerting apredetermined adjustable pressure against saidfchamber tending toprevent expansion thereof.

9. In a device of the character described, a tube system comprising abulb communicating with a pressure responsive element through acapillary tube, a vaporizable liquid normally illling said element andsaid capillary tube as Well as a portion only of said bulb, and anexpansible chamber communicating with said tube system, said chamberbeing responsive only to predetermined excessive pressures developed insaid s 'ystem and being expansible to such a volume-as to permit saidliquid to pass completely out of said bulb when the bulb is heatedbeyond a given temperature.

l0. In a device of the character described, a tube system comprising abulb communicating with a pressure responsive element through acapillary tube, a thermosensitive liquid normally filling said elementand said capillary tube as well as a portion only of said bulb a chambercommunicating with said tube system, said chamber being expansible undervaor pressure in said tube system to such a volume as to permit saidliquid to pass completely out of said bulb when the bulb is heatedbeyond a given temperature, means for exerting a predeterminedadjustable pressure against said chamber tending to prevent expansionthereof, and means responsive to varying temperature conditions around aportion of said tube system exclusive of said bulb for varying thevolume of said chamber.

1l. In a device of the character described, a tube system comprising abulb communicating with a pressure responsive element through acapillary tube, a vaporizable liquid normally filling said element andsaid capillary tube as well as a portion only of said bulb, and anexpansible chamber communicating with said tube system, said chamberbeing responsive only to predetermined excessive pressures developed insaid system and being expansible to such a volume as to permit saidliquid to pass completely out oi' said bulb when the bulb is heatedbeyond a given temperature, and means responsive to varying temperatureconditions around a portion of said tube system exclusive of said bulbfor varying the volume of said chamber.

LAWRENCE E. SMI'H.

DISCLAIMER 2,053,974.-Lawrence E. Smith, Rochester, N. Y. T EMPFJRATURERESPONSIVE DEVICE. Patent dated September 8, 1936. Dleclalmer ledFebruary 9, 1938, by the assignee, Taylor Instrument Companies. Herebyenters this disclaimer to claims 8 and 9 in the specification.

[Oficial Gazette March 8, 1.938.]

